1. Field of the Invention
The present invention relates to an inverted pendulum type vehicle operable to move on a floor surface. More particularly, the present invention relates to an inverted pendulum type vehicle including a control device, which operable to perform a turning processing of the vehicle when a predetermined steering operation is performed and also when an external force is applied about a yaw axis of the vehicle.
2. Description of the Background Art
There is known inverted pendulum type vehicle in which an occupant boarding member capable of tilting with respect to a vertical direction is assembled to a base to which a moving operation part for moving on a floor surface and an actuator device for driving the moving operation part are assembled. An example of such known inverted pendulum type vehicle is disclosed in the PCT Patent Publication No. WO2011/33575.
The inverted pendulum type vehicle controls the moving operation of the moving operation part in such a form as to move the fulcrum of an inverted pendulum in order to prevent the occupant boarding member on which an occupant is boarded from inclining to fall down.
In the PCT Patent Publication No. WO2011/33575, for example, an inverted pendulum type vehicle has been proposed by the present applicant, which can be moved on a floor surface in all directions including the forward-rearward direction and the left-right direction of an occupant by driving a (first) moving operation part according to the tilting of an occupant boarding member or the like.
A conventional inverted pendulum type vehicle, such as shown in the PCT Patent Publication No. WO2011/33575, allows an occupant to turn the vehicle by moving the upper body of the occupant in such a manner as to change the moving direction of the vehicle gradually, but generally requires skillful steering techniques of the occupant in order to make the turn smoothly.
Thus, for a smooth turn, a (second) moving operation part (which will hereinafter be referred to as an “auxiliary moving operation part”) that is coupled to the base such that an interval exists between the auxiliary moving operation part and the first moving operation part present in the forward-rearward direction and which can move in all the directions including the forward-rearward direction and the left-right direction may be added to the vehicle, and control may be performed so as to impart a driving force to the auxiliary moving operation part so that the auxiliary moving operation part can move in at least the left-right direction. In this case, the vehicle can be turned smoothly by controlling the first moving operation part and the auxiliary moving operation part such that the auxiliary moving operation part has a different velocity from the moving operation part in the left-right direction.
However, the first moving operation part and the auxiliary moving operation part are controlled so as not to move in a state in which no steering operation for moving or turning the vehicle is performed, such as during a stop, for example. In such a state, even when the occupant attempts to make a turn (including a change of direction) by adding an external force to the vehicle with one foot of the occupant touched to the floor surface, it is difficult to turn the vehicle because the movements of the first moving operation part and the auxiliary moving operation part are suppressed.
The present invention has been made in view of such a background. Accordingly, it is one of the objects of the present invention to provide an inverted pendulum type vehicle that makes it possible to turn the vehicle easily even in a state in which no steering operation is performed.